Herman Goering's love of wartime loot has come back to haunt modern Germany after it emerged a rug acquired by the Luftwaffe commander still lay in Angela Merkel's office.

The Persian rug had lain undisturbed for decades in the chancellor's office until journalists from the news magazine Der Spiegel uncovered its origins.

Spiegel estimates that the rug could be one of an estimated 600 pieces of furniture and art work plundered during the war still lying in German government buildings.

During the Second World War Nazi Germany launched one of the biggest campaigns of looting ever seen in history. Museums and stately homes, especially those in Eastern Europe, were systematically stripped clean, while the valuable possessions of Holocaust victims also made their way to the private collections of leading Nazis.

Goering was an enthusiastic recipient of stolen booty, and amassed a huge collection of paintings, tapestries and jewellery during the course of the war.

Although Spiegel reported that the Goering rug will soon be removed from Mrs Merkel's office, just how it got there remains unclear, and the news of its presence comes as an unwanted embarrassment to the chancellor and the German government.

Michael Naumann, a former German culture minister, said the government must act to return looted property to its rightful owners or their heirs.

"The legislature must prioritise their return," he said. "More money must also be used for research in German museums." But returning works of looted art can be a fraught procedure. The death and chaos of the Second World War along with the passing of the years means that in many cases just who owned a particular item is lost to history.